Abstract: DESCRIPTION: (adapted from the application): This project proposes to examine the relationships between longevity, nutrition, and reproduction in the Medkerranean fruit fly. It will be framed around the recent finding that the life history of female medflies can be characterized by two physiological modes with different demographic schedules of fertility and survival: (I) a waiting mode in which both mortality and reproduction are low; and (ii) a reproductive mode in which mortality is very low at the onset of egg laying but accelerates as eggs are laid. The project will involve Drs. James Carey (UC Davis), Lawrence Harshman (University of Nebraska) and Linda Partridge (University College London) with data gathered at the Moscamed mass rearing facility in Tapachula, Mexico under the direction of Dr. Pablo Liedo. Professors Hans Muller and Jane-Ling Wang (Division of Statistics, UC Davis) will assist with data management and statistical analyses. The specific aims are to test the following hypotheses: (1) The interplay of aging modes will have fundamentally different effects on the life history characteristics of females: a. Females will live longer when they experience both modes of aging than if they experience one exclusively. b. females will lay more eggs in their lifetimes when they experience only the reproductive mode with continuous feeding on a full diet. c. The local characteristics of the mortality trajectory such as the timing of the mortality "shoulder" or the peak will shift when females experience both modes of aging; (2) The effects of dietary restriction on longevity are mediated through reductions in reproductive rates and costs; (3) The genes and mechanisms elevating longevity in waiting and reproductive mode are different, and possibly mutually exclusive; and (4) the effects of nutrition and reproduction on survival rates are mediated through changes in numbers of active ovadoles, modulations of yolk protein synthesis, and changes in hormone titers.